package org.eclipse.swt.widgets;

/*
 * (c) Copyright IBM Corp. 2000, 2001.
 * All Rights Reserved
 */

import org.eclipse.swt.internal.*;
import org.eclipse.swt.internal.win32.*;
import org.eclipse.swt.*;
import org.eclipse.swt.widgets.*;

/**
 * Instances of this class allow the user to navigate
 * the file system and select a directory.
 * <p>
 * IMPORTANT: This class is intended to be subclassed <em>only</em>
 * within the SWT implementation.
 * </p>
 */

public class DirectoryDialog extends Dialog {
	String message = "", filterPath = "";
	String directoryPath;
	
/**
 * Constructs a new instance of this class given only its
 * parent.
 * <p>
 * Note: Currently, null can be passed in for the parent.
 * This has the effect of creating the dialog on the currently active
 * display if there is one. If there is no current display, the 
 * dialog is created on a "default" display. <b>Passing in null as
 * the parent is not considered to be good coding style,
 * and may not be supported in a future release of SWT.</b>
 * </p>
 *
 * @param parent a shell which will be the parent of the new instance
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 */
public DirectoryDialog (Shell parent) {
	this (parent, SWT.PRIMARY_MODAL);
}

/**
 * Constructs a new instance of this class given its parent
 * and a style value describing its behavior and appearance.
 * <p>
 * The style value is either one of the style constants defined in
 * class <code>SWT</code> which is applicable to instances of this
 * class, or must be built by <em>bitwise OR</em>'ing together 
 * (that is, using the <code>int</code> "|" operator) two or more
 * of those <code>SWT</code> style constants. The class description
 * for all SWT dialog classes should include a comment which
 * describes the style constants which are applicable to the class.
 * </p>
 * Note: Currently, null can be passed in for the parent.
 * This has the effect of creating the dialog on the currently active
 * display if there is one. If there is no current display, the 
 * dialog is created on a "default" display. <b>Passing in null as
 * the parent is not considered to be good coding style,
 * and may not be supported in a future release of SWT.</b>
 * </p>
 *
 * @param parent a shell which will be the parent of the new instance
 *
 * @exception IllegalArgumentException <ul>
 *    <li>ERROR_NULL_ARGUMENT - if the parent is null</li>
 * </ul>
 * @exception SWTException <ul>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the parent</li>
 *    <li>ERROR_INVALID_SUBCLASS - if this class is not an allowed subclass</li>
 * </ul>
 */
public DirectoryDialog (Shell parent, int style) {
	super (parent, style);
}

int BrowseCallbackProc (int hwnd, int uMsg, int lParam, int lpData) {
	switch (uMsg) {
		case OS.BFFM_INITIALIZED:
			if (filterPath != null && filterPath.length () != 0) {
				/* Use the character encoding for the default locale */
				byte [] buffer = Converter.wcsToMbcs (0, filterPath, true);
				OS.SendMessage (hwnd, OS.BFFM_SETSELECTION, 1, buffer);
			}
			if (title != null && title.length () != 0) {
				/* Use the character encoding for the default locale */
				byte [] buffer = Converter.wcsToMbcs (0, title, true);
				OS.SetWindowText (hwnd, buffer);
			}
			break;
		case OS.BFFM_VALIDATEFAILED:
			byte [] buffer1 = new byte [256];
			OS.MoveMemory (buffer1, lParam, 256);
			/* Use the character encoding for the default locale */
			char [] buffer2 = Converter.mbcsToWcs (0, buffer1);
			int length = 0;
			while (length < buffer2.length && buffer2 [length] != 0) length++;
			directoryPath = new String (buffer2, 0, length);
			break;
	}
	return 0;
}

/**
 * Returns the path which the dialog will use to filter
 * the directories it shows.
 *
 * @return the filter path
 */
public String getFilterPath () {
	return filterPath;
}

/**
 * Returns the dialog's message, which is a description of
 * the purpose for which it was opened. This message will be
 * visible on the dialog while it is open.
 *
 * @return the message
 */
public String getMessage () {
	return message;
}

/**
 * Makes the dialog visible and brings it to the front
 * of the display.
 *
 * @return a string describing the absolute path of the selected directory,
 *         or null if the dialog was cancelled or an error occurred
 *
 * @exception SWTException <ul>
 *    <li>ERROR_WIDGET_DISPOSED - if the dialog has been disposed</li>
 *    <li>ERROR_THREAD_INVALID_ACCESS - if not called from the thread that created the dialog</li>
 * </ul>
 */
public String open () {
	
	/* Initialize OLE */
	OS.OleInitialize (0);
	
	int hHeap = OS.GetProcessHeap ();
	
	/* Get the owner HWND for the dialog */
	int hwndOwner = 0;
	if (parent != null) hwndOwner = parent.handle;

	/* Copy the message to OS memory */
	int lpszTitle = 0;
	if (message != null && message.length () != 0) {
		/* Use the character encoding for the default locale */
		byte [] buffer = Converter.wcsToMbcs (0, message, true);
		lpszTitle = OS.HeapAlloc (hHeap, OS.HEAP_ZERO_MEMORY, buffer.length);
		OS.MoveMemory (lpszTitle, buffer, buffer.length);
	}

	/* Create the BrowseCallbackProc */
	Callback callback = new Callback (this, "BrowseCallbackProc", 4);
	int address = callback.getAddress ();
	
	/* Open the dialog */
	directoryPath = null;
	BROWSEINFO lpbi = new BROWSEINFO ();
	lpbi.hwndOwner = hwndOwner;
	lpbi.lpszTitle = lpszTitle;
	lpbi.ulFlags = OS.BIF_RETURNONLYFSDIRS | OS.BIF_EDITBOX | OS.BIF_VALIDATE;
	lpbi.lpfn = address;
	int lpItemIdList = OS.SHBrowseForFolder (lpbi);
	if (lpItemIdList != 0) {
		byte [] buffer = new byte [256];
		if (OS.SHGetPathFromIDList (lpItemIdList, buffer)) {
			/* Use the character encoding for the default locale */
			char [] path = Converter.mbcsToWcs (0, buffer);
			int length = 0;
			while ((length < path.length) && (path [length] != 0)) length++;
			directoryPath = new String (path, 0, length);
		}
	}

	/* Free the BrowseCallbackProc */
	callback.dispose ();
	
	/* Free the OS memory */
	if (lpszTitle != 0) OS.HeapFree (hHeap, 0, lpszTitle);

	/* Free the pointer to the ITEMIDLIST */
	int [] ppMalloc = new int [1];
	if (OS.SHGetMalloc (ppMalloc) == OS.S_OK) {
		/* void Free (struct IMalloc *this, void *pv); */
		OS.VtblCall (5, ppMalloc [0], lpItemIdList);
	}
	
	/* Uninitialize OLE */
	OS.OleUninitialize ();
	
	/*
	* This code is intentionally commented.  On some
	* platforms, the owner window is repainted right
	* away when a dialog window exits.  This behavior
	* is currently unspecified.
	*/
//	if (hwndOwner != 0) OS.UpdateWindow (hwndOwner);
	
	/* Return the directory path */
	return directoryPath;
}

/**
 * Sets the path which the dialog will use to filter
 * the directories it shows to the argument, which may be
 * null.
 *
 * @param string the filter path
 */
public void setFilterPath (String string) {
	filterPath = string;
}

/**
 * Sets the dialog's message, which is a description of
 * the purpose for which it was opened. This message will be
 * visible on the dialog while it is open.
 *
 * @param string the message
 */
public void setMessage (String string) {
	message = string;
}

}
